path: root/drivers/usb/core/usb.c

/*
 * drivers/usb/core/usb.c
 *
 * (C) Copyright Linus Torvalds 1999
 * (C) Copyright Johannes Erdfelt 1999-2001
 * (C) Copyright Andreas Gal 1999
 * (C) Copyright Gregory P. Smith 1999
 * (C) Copyright Deti Fliegl 1999 (new USB architecture)
 * (C) Copyright Randy Dunlap 2000
 * (C) Copyright David Brownell 2000-2004
 * (C) Copyright Yggdrasil Computing, Inc. 2000
 *     (usb_device_id matching changes by Adam J. Richter)
 * (C) Copyright Greg Kroah-Hartman 2002-2003
 *
 * NOTE! This is not actually a driver at all, rather this is
 * just a collection of helper routines that implement the
 * generic USB things that the real drivers can use..
 *
 * Think of this as a "USB library" rather than anything else.
 * It should be considered a slave, with no callbacks. Callbacks
 * are evil.
 */

#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/string.h>
#include <linux/bitops.h>
#include <linux/slab.h>
#include <linux/interrupt.h>  /* for in_interrupt() */
#include <linux/kmod.h>
#include <linux/init.h>
#include <linux/spinlock.h>
#include <linux/errno.h>
#include <linux/usb.h>
#include <linux/usb/hcd.h>
#include <linux/mutex.h>
#include <linux/workqueue.h>
#include <linux/debugfs.h>

#include <asm/io.h>
#include <linux/scatterlist.h>
#include <linux/mm.h>
#include <linux/dma-mapping.h>

#include "usb.h"


const char *usbcore_name = "usbcore";

static bool nousb;	/* Disable USB when built into kernel image */

/* To disable USB, kernel command line is 'nousb' not 'usbcore.nousb' */
#ifdef MODULE
module_param(nousb, bool, 0444);
#else
core_param(nousb, nousb, bool, 0444);
#endif

/*
 * for external read access to <nousb>
 */
int usb_disabled(void)
{
	return nousb;
}
EXPORT_SYMBOL_GPL(usb_disabled);

#ifdef	CONFIG_PM
static int usb_autosuspend_delay = 2;		/* Default delay value,
						 * in seconds */
module_param_named(autosuspend, usb_autosuspend_delay, int, 0644);
MODULE_PARM_DESC(autosuspend, "default autosuspend delay");

#else
#define usb_autosuspend_delay		0
#endif


/**
 * usb_find_common_endpoints() -- look up common endpoint descriptors
 * @alt:	alternate setting to search
 * @bulk_in:	pointer to descriptor pointer, or NULL
 * @bulk_out:	pointer to descriptor pointer, or NULL
 * @int_in:	pointer to descriptor pointer, or NULL
 * @int_out:	pointer to descriptor pointer, or NULL
 *
 * Search the alternate setting's endpoint descriptors for the first bulk-in,
 * bulk-out, interrupt-in and interrupt-out endpoints and return them in the
 * provided pointers (unless they are NULL).
 *
 * If a requested endpoint is not found, the corresponding pointer is set to
 * NULL.
 *
 * Return: Zero if all requested descriptors were found, or -ENXIO otherwise.
 */
int usb_find_common_endpoints(struct usb_host_interface *alt,
		struct usb_endpoint_descriptor **bulk_in,
		struct usb_endpoint_descriptor **bulk_out,
		struct usb_endpoint_descriptor **int_in,
		struct usb_endpoint_descriptor **int_out)
{
	struct usb_endpoint_descriptor *epd;
	int i;

	if (bulk_in)
		*bulk_in = NULL;
	if (bulk_out)
		*bulk_out = NULL;
	if (int_in)
		*int_in = NULL;
	if (int_out)
		*int_out = NULL;

	for (i = 0; i < alt->desc.bNumEndpoints; ++i) {
		epd = &alt->endpoint[i].desc;

		switch (usb_endpoint_type(epd)) {
		case USB_ENDPOINT_XFER_BULK:
			if (usb_endpoint_dir_in(epd)) {
				if (bulk_in && !*bulk_in) {
					*bulk_in = epd;
					break;
				}
			} else {
				if (bulk_out && !*bulk_out) {
					*bulk_out = epd;
					break;
				}
			}

			continue;
		case USB_ENDPOINT_XFER_INT:
			if (usb_endpoint_dir_in(epd)) {
				if (int_in && !*int_in) {
					*int_in = epd;
					break;
				}
			} else {
				if (int_out && !*int_out) {
					*int_out = epd;
					break;
				}
			}

			continue;
		default:
			continue;
		}

		if ((!bulk_in || *bulk_in) &&
				(!bulk_out || *bulk_out) &&
				(!int_in || *int_in) &&
				(!int_out || *int_out)) {
			return 0;
		}
	}

	return -ENXIO;
}
EXPORT_SYMBOL_GPL(usb_find_common_endpoints);

/**
 * usb_find_alt_setting() - Given a configuration, find the alternate setting
 * for the given interface.
 * @config: the configuration to search (not necessarily the current config).
 * @iface_num: interface number to search in
 * @alt_num: alternate interface setting number to search for.
 *
 * Search the configuration's interface cache for the given alt setting.
 *
 * Return: The alternate setting, if found. %NULL otherwise.
 */
struct usb_host_interface *usb_find_alt_setting(
		struct usb_host_config *con